Safety-envelop



Patented Nov. 22, I898. M. KROELL.

SAFETY ENVELOP. (Applicfition filed June 21, 1898.)

(No Model.)

llllllll-I Ill EA v (Attorney NITED STATES PATENT OFFICE.

MARZEL KROELL, OF LOUISVILLE, KENTUCKY.

SAFETY-ENVELO P.

SPECIFICATION forming part of Letters Patent No. 614,728, dated November 22, 1898.

A li ati fil d June 21, 1898. Serial No. 684,076. (No model.)

To ctZZ whom it may concern:

Be it known that I, MARZEL KROELL, a citizen of the United States, residing at Louisville, in the county of Jefferson and State of Kentucky, have invented new and useful Improvements in Safety-Envelops, of which the following is a specification.

The object of my invention is to provide an envelop which cannot be opened surreptitiously without leaving marks to show that it has been tampered with.

It consists in the novel features of construction and combination of parts hereinafter described, reference being had to the accompanying drawings, in which I have shown my invention as applied to ordinary commercial and correspondence envelops, and is fully disclosed in the following description and claims.

In the drawings, Figure l-is a plan view of the front of an envelop-blank embodying my invention. Figs. 2, 3, 4, and 5 are similar plan views showing the successive steps of folding to form the envelop, and Fig. 6 shows the front of an envelop embodying my invention as it will appear fully folded.

Similar letters refer to similar parts throughout the several drawings.

A represents the part of the blank constituting the back of the envelop. A, A A and A represent flaps of the blank adapted to fold in toward the part A and form the envelop.

A represents a supplementary security-flap pasted to the lower edge of the upper fiap A and adapted to fold down over a letter placed in the envelop.

13 represents a fastener made of a thin narrow strip of aluminium or tin passed through two parallel slits in the end flap A, constituting a fastening-band, the said slits being parallel to the line 6, on which the end flap A is inwardly folded.

0 represents a diagonal slit in the end flap A parallel to a similar slit 0 in the end flap A 0 represents a slit in the side flap A made perpendicular to the lower folding-line e of the blank, dividing the outer part of the flap into two locking-flaps a, formed with an angular projection f and a, formed as shown.

a and a are minor locking-flaps formed on the lower outer part of the end flap A On the part a are stamped two letters,,preferably O. K., in any color that is not fast, and to the locking-flap a is attached a spring D, made of a thin narrow strip of tin or aluminium, having its free end toward a and fastened at the other end to the blank by bending and held in place by passing through parallel slits in a forming retaining-bands. The lines 6 e e and the dotted lines in Fig. 1 represent lines of folding.

formed into an envelop, the tin or aluminium strip B is bent at each slit through which it passes at right angles, forming three sides of a rectangle.

The letters I) b b I) represent slits where the upturned free ends of B pass through the blank in folding.

pared, as described, to make the envelop, the end flap A is folded inwardly on A at the line e, having the two ends of B projecting perpendicularly upward from it, and the flap A is also folded inwardly on A and A,when the slits c and 0 will register. The lockingflap a carrying the spring D, is then folded backwardly upon the flap a on the dotted line shown between them in the drawings, and the flap (1 carrying a along, is bent perpendicularly-up on the dotted line separating it from A in the drawings, Fig. 1. The part of A above the slit 0 is then pulled back, as shown in Fig. 2, to admit the folding upward and in of the side flap A As this is folded the minor locking-flap a, having the projection F, is passed through the slit 0 and under the flap A, from which the projection f prevents it from being withdrawn, andthe locking-flap a will lie on top of the end flap A and one prong of the fastener B will pass through the slot b,which is adjacent to the slit 0 The pulled-back part of the end flap A is then pressed down to pass over the projecting ends of the fastener B at the points I) b, as shown in Fig. 3, and then the locking-flap a of the side flap A is folded over onto A and the projecting ends of the fastener 13, passing through it at the points indicated, are firmly .flattened down on the paper, thusholding the folds securely together. The covering side When it is desired to fold the blank thus The blank having been formed and preflap A is provided with sticking-gum along its inner edges, as usual. The envelop is now formed, as in Fig. a, and ready to receive a letter. The letter is inserted and the securityflap A (shown in Fig. 1) is folded down over it inside the envelop. The covering-flap A is then folded, with the gum moistened, as usual, and, if desired, the prongs of the fastener B may be bent upwardly to pass through the slots Z) Z) in the flap A and then be again folded down upon the flap. The locking-flap a bearing the spring-strip D, is then inserted under the edge of A through the slit 0, when it will lie upon the locking-flap a, and the free end of the spring-strip D will enter the slot f in the flap a if an attempt is made to withdraw the locking-flap a It is evident that an envelop thus constructed cannot be opened by a knife without showing that it has been tampered with, and if an attempt is made to open it by steaming or wetting the colors in the letters on the flap a will run and spread.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A safety-envelop consisting of a blank having two foldable end flaps provided with a locking-slit and a locking metal strip on one and a locking-slit and locking-tabs on the other, one carrying a metal spring-strip, as shown, and the otherstamped with letters in running colors, and a bottom side flap formed with two locking-flaps one adapted to engage the slits in the end flaps when folded and the other to fold over the inner part of the end flap that carries the metal spring and letters, and be fastened by the metal lockingstrip, and two top side flaps, one adapted to be folded down over a letter inclosed in the envelop and the other provided with sticking-gum on its face adapted to fold over the part fastened by the metal strip and close the envelop and be held in place by the locking-flap, carrying the metal spring, passing below it and through the slits in the folded end flaps leaving the letters stamped with running colors exposed, substantially as described and for the purposes specified.

2. A safety-envelop formed from a blank having two foldable end flaps, one provided with a locking-slit and a locking metal strip, and the other having a locking-slit, slots to receive the metal strip on the other flap, and a locking-tab carrying a metal spring-strip, a bottom flap with two lockingflaps, one adapted to enter the locking-slits in the end flaps and having a slot to receive the free end of the spring-strip when the parts are folded into position, and the other to fold over the inner part of the end flap that carries the spring-strip and be fastened by the locking metal strip, and a top flap adapted to fold over onto the parts fastened by the lockingstrip and having its edges gum med, substantially as described.

Signed by me, in the presence of two witnesses, at Louisville, Kentucky, this (3th day of June, 1898.

MARZEL KROELL.

Witnesses: v

\VILL M. DIETZMAN, G. W. HERBERT. 

